Side impacts account for approximately one-third of all vehicle crashes. Generally, side impacts are potentially injurious to the vehicle occupants due to the close proximity of the occupants to the impacted structure. In addition to providing adequate side structural stiffness, automotive manufacturers employ side airbags, side curtains and other occupant protection systems to provide enhanced occupant protection. However, due to the close proximity of the occupants, these occupant protections systems have only a few milliseconds for full deployment before the side structure infringes upon the vehicle occupant compartment. The benefits of pre-crash sensing, which provides additional time for proper deployment of side occupant protection systems are well understood. The challenge is to provide reliable and affordable pre-crash sensing for side impact protection systems.
To meet wide-angle coverage requirements for pre-crash sensing purposes, multiple pulsed radar-based sensing systems are being investigated for automotive applications. Radar sensors with mechanically or electronically scanning antennas are also under consideration for accurately tracking objects in the field of view of the radar sensors on a real-time basis for reliable countermeasure activation and to minimize false alarms. Such radar sensor systems, however, are relatively expensive, and may not be viable for some vehicle platforms.
The need for more affordable radar-based collision avoidance systems has made it apparent that a new technique to minimize collision damage is needed. The new technique should accurately predict a target vehicle position with respect to a host vehicle, substantially minimize the time between an anticipated unavoidable collision detection and subsequent activation of safety devices, and be less expensive than mechanically scanning or electronically scanning radar-based collision sensing systems or systems with multiple radar sensors. The present invention is directed to these ends.